What I would love is a 'lock right' style diff center. These work like a detroit locker. I came across this kit for Suzuki Escudo (Vitara over here) and it got me thinking...
How hard would it be to machine something similar to fit in a swingaxle diff housing and use the stock side gears?
This is a not a progressive LSD like a torsen or plate style, but for broken/slippery surfaces it would be pretty good.
P.s. I posted this in the trans forum too. Hopefully we could work something out with this...